Remote control circuit



Oct. 5, 1943. w. R. SMITH REMOTE CONTROL CIRCUITS H 2 N H v v F??? a MWK-' I 3mm Oct. 5, 1943. w. R. SMITH REMOTE CONTROL CIRCUITS.

Filed Marbh 24, 1941 2 Sheets-Sheet 2 Patented Oct. 5, 1943 UNITEDSTATES PATENT OFFICE REMOTE CONTROL CIRCUIT William Russell Smith,Philadelphia, Pa., assignor to The A. 0. Gilbert Company, New Haven,Conn., a corporation of Maryland Application March 24, 1941, Serial No.384,794

4 Claims.

poses, supplied by a small rectifier and acting upon a so-called D. C.relay-controlling the 'operation of an electromagnetic control device.In such cases there has been a good deal of trouble with the relay forvarious reasons, one of which is that such a relay has to be verysensitive, and the required sensitivity is difiicult to obtain and alsoto maintain. The operation of the relay has also been adversely affectedby the occurrence of various external conditions.

Another objection to prior control circuits of the kind mentioned hasbeen that in many instances there has been undue heating of therectifler, and in cases where three-position reversing and stoppingswitches have been employed for the control of propelling motors andlike A. C.

motors, there has been sticking or other faulty operation of suchswitches.

One of the objects of my invention is to simplify and improve remotecontrol circuits and apparatus of the type mentioned above.

Another purpose which I have in view is the elimination of thepreviously mentioned difiiculties and drawbacks.

More particularly it is an object of my invention to provide a simpleremote control apparatus for an A. C.-operated motor or appliance inwhich there is a unidirectional control current, but wherein,nevertheless, the relay or relays previously used in connection withsuch current are dispensed with.

Yet another object is to furnish a simple and inexpensive control fortoy trains in which the reversing switch or like controlling device hasits control and operation limited and protected in such a manner thatthe operation of the motor or other appliance will not be adverselyaffected by external conditions which have heretofore been prejudicial.It the motor being controlled is a propelling motor having associatedtherewith the usual three-position switch, the operation of the devicewill be considerably improved as a result or the fact that the switchwill not be inadvertently operated as a result of the interruption ofthe current supplied to the motor.

To these and other ends the invention consists in thenovel features andcombinations of parts and new procedure to be hereinafter described andclaimed.

In the accompanying drawings:

Fig. l is a diagram of a toy train circuit embodying my improvements;

Fig. 2 shows a somewhat modified and simpler circuit embodying myinvention; and

Fig. 3 shows a further modified form.

In the form of my invention shown in Fig. l, the improvements areapplied to the control from a remote point of the starting and stoppingof a toy locomotive running on rails supplied with alternating current,and in this particular instance the propelling motor is controlled by athree-position switch of well-known type employing a ratchet device andadapted in one position to cause rotation of the motor in one direction,in the next position to stop the motor, and in the next position tocause rotation of the motor in the opposite direction.

In Fig. 1 the track rails are indicated at A and B, respectively, thetransformer supplying alterhating current at C, the locomotive at D, andthe remote control device for the propelling motor at E, thisla'stdevice in this particular case comprising a push button switch mountedin a separate casing and adapted to be positioned at any desired pointalong the track. The locomotive not only carries the propelling motor,indicated generally at F, but, also a three-position switch, indicatedgenerally at G, operating in the manner above mentioned. This switch Gmay be of any appropriate kind for the purposes in view, but I prefer touse a switch of the kind shown in McLoughlin Patent No. 2,196,319 ofApril 9, 1940. This switch comprises an electrolnagnet i0 adapted to acton a pivoted arm Ii, the free end portion of which engages a ratchetwheel i 2 connected to a commutator drum i3.

The field winding ll of the motor is connected by circuit leg I5, havinga suitable collecting shoe, to rail A. From the opposite end of windingM a circuit leg I6 is connected to a collecting shoe bearing against thecommutator drum. A circuit leg I! connects the commutator drum to rail13. The armature'of the motor is connected at opposite sides to circuitlegs or branches I8 and i9, respectively, supplied with collecting shoesbearing against the commutator. The coil or winding of electromagnet I0is connected with rail B by leg or branch 20, and the oppo- 'rail Athrough leg or AVAILABLE COPY site end of the coil or winding isconnected with branch 2!, but in this leg or branch a half-waverectifier R, preferably of the multiple plate or disk type, isinterposed, which, under certain conditions, as hereinafter described,passes unidirectional current for operating the three-position switch.In Fig. 1 I have shown the three-position switch in a position tooperate the motor. Upon the next actuation of ratchet I2 by the switcharmature H the supply of current to the motor will be arrested, and uponthe following actuation the motor will be connected for rotation in thereverse direction.

The transformer C can be of the usual type, having a primary Winding Cand a secondary C the latter being controlled by an adjustable knob 22to supply voltage within certain limits,

say from '7 to 14 volts, this, however, being only by way of example.One end of the secondary C is connected to rail A by leg 23. Knob 22 isconnected by leg 24 to a push button switch S forming a part of theremote control device E. Leg 24 is connected to a contact leaf 25normally held in the position shown in Fig. l, in which it makes contactwith a contact member 26 in the box or casing of the switch. A pushbutton member 21 may be used to separate leaf 25 from contact member 26and push it into engagement with another contact member 28. Associatedwith the push button switch and preferably in the casing or box of thecontrol device is a half-wave rectifier R, preferably of the multipleplate or disk type, connected at one side to contact member 26 by leg29, and connected at the other side by leg 30 with rail 13. Contactmember 28 is connected to circuit leg 30 at point 3|, which is locatedbetween rectifier R and rail B, so that upon depression of push button21 rectifier R can be by-passed or short-circuited.

In accordance with my invention the motor or other appliance to becontrolled is provided with a control device employing unidirectionalcurrent of small voltage, but this control device under normalconditions has its circuit blocked so as notto pass the unidirectionalcurrent. However, when it'is desired to operate the motor or otherappliance the blocking against the unidirectional current is removed sothat such current passes in one direction to operate the con- .roldevice, which in turn causes the desired op- :iration or control of themotor.

In the form described above, in which the rectifiers R and R areemployed, one of these rectifiers, namely, R, is in the circuit of thecontrol device G, while the other, R, is in the main; motor circuitunder normal conditions, that is to say, when push button 21 is in thenormal position. These rectifiers are placed in such relation to eachother as to block the flow of unidirectional current into the controldevice. One rectifier prevents the flow of this current into the controldevice from one side, and the other rectifier prevents current frompassing in from the other side, thus bringing about a blocked orbalanced condition of the control device. However, when it is desired tooperate the control device, all that is necessary is the depression ofthe push button 21, which will short-circuit the rectifier R and causean instantaneous fiow of operating current to the control device Gthrough the rectifier R. In this particular case the current passingthrough rectifier R will pass from rail A, and will go from therectifier through the winding II) to rail B. The desired actuation ofthe control device having been accomplished,

21 is released and moves back by spring action to the position shown inFig. 1 so as to restore rectifier R to the circuit in blocking relationto the other rectifier.

In operating the control device the half-wave rectifier which is active,namely, rectifier R, will obviously pass a reduced voltage to thecontrol device from the rails, and therefore if at a given time theoperating voltage is, say, 15 volts, the control operating voltage willbe approximately 7 volts.

For the purpose of preventing the magnet ID from being afiected by strayalternating currents or surges, shading disks 3V, or similar devices,may be employed.

Owing to the fact that in half-wave rectifiers of the multiple plate ordisk type there is appreciable leakage, some A. C. current will fiowfrom the transformer to the motor by way of rectifier R, and the motorwill be operated by a pulsating current which is a combination of A. C.and unidirectional. The sine wave has distinct jagged portions below theline indicating some flow of A. C.

In the form shown in Fig. 2, a simplified arrangement is shown in whicha motor H is supplied with operating current from a source I by circuitlegs indicated at 32 and 33. Circuit leg 32 is connected directly to themotor, and has interpolated therein a rectifier R Circuit leg 33 hasinterpolated therein a rectifier R and circuit leg 33 is connected to anelectromagnetic switch device G. The rectifiers R and R pass current inopposite directions, as in the case first described, the arrangementbeing such that under normal conditions no control operatingunidirectional current flows in the control portion of the circuit.However, when it is desired to actuate the control device, ashort-circuiting connection 34 having a manual switch 35 can be used forshort-circuiting rectifier R and causing unidirectional controllingcurrent to pass through rectifier R In Fig. 3, I have shown a controlcircuit for use with toy trains which is generally similar to thatillustrated in Fig. 1, although differing in detail. In this case twooppositely acting halfwave rectifiers are employed, but they are bothplaced directly in the circuit of the controlling device, and they bringabout a blocked or balanced condition in the control circuit which isovercome by the passage of a current having a sufiiciently high voltageto pass through one of the rectifiers and establish a current fiow. Inthis form, track rails A and B are employed, and the locomotive D isprovided with a propelling motor F, the field winding of which on oneside is connected to rail A, while connection of the motor to rail B isthrough circuit leg 36, which cooperates with the commutator push buttondrum 31 of an electromagnetic starting, stopping and reversing switch GThis switch G has an electromagnet 38 connected to rails A and B throughcircuit legs 39 and 40, respectively. In circuit leg 39 is interpolateda rectifier R and in leg 40 is interpolated in blocking or neutralizingrelation to rectifier Rt Alternating current is supplied to the rails bya transformer T having a primary 4|, a secondary 42, and an adjustableknob 43 controlling the secondary. In a suitable box or casing is acontrol device E having a push button switch mechanism S. Within thecasing of control device E' is an auto transformer U,which uponactuation of switch mechanism S is adapted to a rectifier R i impressadditional voltage upon the rails. The auto transformer comprises a mainwinding 44, and a subsidiary winding 45 in which current can be inducedfrom the main winding, and winding 44 is connected to terminal 46 oftransformer T by leg 41. Terminal or post 48 of transformer T isconnected by leg 49 to the junction 50 of windings 44 and 45. Theopposite end of winding 45 is connected by leg to spring contact leaf 52underlying a push button 53. Spring leaf 52 is adapted to press againsta leaf 54 in order to make contact therewith, and then press leaf 54 outof contact with a fixed contact member 55 which is connected by leg 56to the middle or knob terminal 51 of transformer T. Leaf 54 is connectedwith rail A by leg or lead 54.

The rectifiers R and R are theoretically of equal capacity, and undernormal conditions prevent flow of unidirectional current throughelectromagnet 38. However, when it is desired to actuate the controldevice, push button 53 is depressed, which has the efiect of introducingsecondary winding 45 into the track circuit, thus increasing thevoltage, say to 24 volts, which is a voltage suflicient to break throughone of the rectifiers R R namely, the weaker of the two, and permitcurrent to pass therethrough. In this manner unidirectional current willpass through the electromagnet 38, and will cause actuation of thecontrol device. The rectifiers R, R will be of the self-healing type sothat after operation involving the break-down of one, the continuity ofthe control circuit will be restored preliminary to a subsequentoperation of the control device. In order to actuate the control devicethe control button need be depressed only momentarily, as the action ofthe additional voltage in breaking through one of the rectifiers will bevery rapid, and, in fact, practically instantaneous, bringing about anextremely quick actuation of the control device, even in the event thatthe control device and the push button are separated by a considerabledistance.

In the case now under discussion it will be apparent that in theordinary running condition of the motor F the operating current will notbe required to pass'through a rectifier, and

this may be considered an advantage in cases where the motor has a smallnumber of poles, and might be subject to greater vibration or noisier ifa rectifier were in series connection with the motor. Where the motorhas a larger number of poles this factor need not be considered. In sucha case, that is, where the motor has as many as say five or seven poles,the fact that a small direct or unidirectional current is carried alongwith the alternating current, as in the case of Fig. 1, would be of noparticular moment from an operating standpoint. However, should it bedesired to operate the motor on alternating current at all times, anarrangement such as shown in Fig. 3 can be use.

In the form shown in Fig. 3 it is understood, of course, that bothrectifiers R, R are carried by the locomotive. These can be smallrectifiers which are quite inexpensive, and the auto transformer orbooster employed in connection with the push button device is also aninexpensive feature of the toy train outfit.

One of the most important advantages of my invention is the completeelimination of D. C. relays used in connection with the electromagneticcontrol device, some of the disadvantages of which relays have beenpreviously mentioned.

There is no need of superimposing direct or unidirectional current on A.C. for control purposes nor of interrupting the supply of A. C. when thecontrol device is to be actuated. In the forms of my invention hereinshown, two rectifiers are required, but these are relativelyinexpensive. Upon actuation of the push button or like switch, theoperation of the control is very quick, certain and positive, andmoreover the control is not adversely affected by a number of factorswhich previously enters into consideration. Heretoiore much trouble andinconvenience has been occasioned by the fact that in a circuitemploying a three-position switch for controlling a propelling motor ofa toy train, the interruption of the supply of operating current, fromone cause or another, would effect an undesired actuation of the switch.The fact that this condition is entirely overcome is an added advantageof my invention. Cutting off the current at the transformer or shortingthe circuit across the rails will not affect the control device.Furthermore, there is much less tendency for the control device to stickas a result of surges of current and the like.

In the cases shown in Figs. 1 and 3 the track rails are intended to beinsulated from each other, but I may of course use a so-called thirdrail acting as one leg of the circuit.

It will be understood that in the broad aspects of the invention I donot limit myself to the control of the operation of motors as distinctfrom other translating devices, and that while in illustrating theinvention I have shown in all cases a three-position control switch ofthe ratchet type, the character of the control device may beconsiderably changed.

While I have shown three forms which the invention may take, it can beembodied in various other forms, and various modifications and changesin the organization of parts and in the details can be made withoutdeparting from the principles of the invention or the scope of theclaims.

one leg connecting said translating device directly with said source, asecond circuit leg having interpolated therein a control means for saidtranslating device operable by unidirectional current and a valve deviceblocking passage of unidirectional current in one direction, a valvedevice in the first-mentioned circuit leg in opposed relation to thefirst mentioned valve device and normally acting while said translatingdevice is in operation to block passage of unidirectional current tosaid control means, and means for shunting out one of said valvedevices.

2. The combination of a translating device, a source of alternatingcurrent, a circuit having one leg connecting said translating devicedirectly with said source, a second circuit leg having interpolatedtherein a control means for said translating device operable byunidirectional current, means blocking the fiow of unidirectionalcurrent through the control means in either direction under normalconditions, and means including a manually operable member located at adistance from the control means for overcoming the action of saidblocking means, said blocking means comprising opposed rectifiers, andsaid overcoming means including means for shortcircuiting one of therectifiers.

3. In an operating and controlling circuit for toy trains,

the combination of a transformer supplying alternating current, acircuit including rails supplied with alternating current from thetravels, said circuit said second rectifier.

4. In an operating and controlling circuit for toy trains, thecombination of a transformer supplyingvalternating current, a circuitincluding rails supplied with alternating current from the transformerand on which the train travels, said train carrying a motor and acontrol device for said motor operable by unidirectional current, arectifier adapted to pass current in the circuit in one direction only,a second and opposed'rectifier adapted to pass current in the oppositedirection only, and means including a manually operable switch locatedat a fixed point along the rails for overcoming the blocking action ofone of said rectifiers so that the other is eflective, both of saidrectifiers being carried by the train,'and said last-named meansincluding a booster device adapted to cause a breakthrough or one ofsaid rectifiers.

WILLIAM RUSSELL SMITH.

